MetService is warning the west of the South Island is likely to see the heaviest rain set to affect large parts of the country this weekend.
The headwaters of the lakes and rivers of Otago and Canterbury are also expected to bear the brunt of the “strong northwesterly flow”, the forecaster warned.
However, large parts of the country are also in the firing line for heavy rain and northwest gales, with a number of weather watches and warnings in place, including a severe thunderstorm watch for many North Island regions.
An orange heavy rain warning is in place for the ranges of the Westland District north of Haast until midnight tonight, with 120 to 140mm of rain expected on top of what has already fallen.
“Peak rates of 20 to 25mm/h expected this morning and afternoon. Snow level about 1800 metres. Further periods of heavy rain are expected from Sunday until Tuesday. Minimal chance of upgrading to a Red Warning,” MetService said.
The headwaters of the Canterbury lakes and rivers from Arthur’s Pass southwards are under the same warning, with 120 to 140mm of rain also expected on top of what has already fallen.
“Peak rates of 20 to 25mm/h expected this morning and afternoon about the divide. Snow level around 1800 metres. Minimal chance of upgrading to a Red Warning.”
An orange heavy rain warning is in place for the Tararua Range from 6pm tonight until 6am tomorrow.
“Expect 70 to 100mm of rain. Peak rates of 25 to 35mm/h expected early Sunday morning. Minimal chance of upgrading to a Red Warning.”
Meanwhile, heavy rain watches are in force for Waikato south of Te Awamutu, Waitomo, Taumarunui, Taupō, northern Taranaki and northern Taihape; Tasman northwest of Motueka, Grey and Buller districts; the Richmond and Bryant Ranges including the Rai Valley, and the ranges of eastern Bay of Plenty and Gisborne/Tairawhiti from this afternoon/evening into Sunday.
Heavy rain watches are also in force for the ranges of the Westland District from Haast southwards; the headwaters of the Otago lakes and rivers, and Fiordland from tomorrow afternoon into Monday.
Strong northwesterly winds prompt warning, watches
Meanwhile, an orange strong wind warning is in place for the Canterbury High Country until 1pm this afternoon.
“Severe gale northwesterlies gusting 120km/h in exposed places. Further severe gales possible from Sunday evening into Monday. Minimal chance of upgrading to a Red Warning.”
Strong wind watches are in place for Taranaki, Taihape, northern Whanganui and inland parts of Hawke’s Bay and Gisborne/Tairawhiti; Tasman District and the Marlborough Sounds, and Wellington and Kapiti Coast from this evening into Sunday.
A strong wind watch is also in place for Otago excluding coastal parts of Clutha, Southland north of Gore and Fiordland tomorrow.
Thunderstorms forecast for many North Island regions
MetService has also said an active front is forecast to move over the North Island during Sunday morning, with thunderstorms forecast for many North Island regions.
As a result, Northland, Auckland, Waikato, Waitomo, Taumarunui, Taupō, Taranaki, Taihape, Wanganui, Manawatu, Tararua, Kapiti-Horowhenua, Wairarapa, Wellington have been placed under a severe thunderstorm watch from midnight tonight until 7am tomorrow morning.
“About central and western parts of the North Island from southern Northland to northern Wellington, there is a risk of some thunderstorms being severe between midnight Saturday and 7.00am Sunday,” the forecaster said.
“Some of these thunderstorms may generate localised downpours of 25 to 40mm/h, especially from Waitomo southwards. Rainfall of this intensity can cause surface and/or flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips. Driving conditions will also be hazardous with surface flooding and poor visibility in heavy rain.
“Some of these thunderstorms may also be squally, and produce damaging wind gusts of 110km/h or stronger. Wind gusts of this strength can cause some structural damage, including trees and power lines, and may make driving hazardous.”
People can keep up to date with the latest weather watches and warnings on the MetService website.